In the computer field, various server platforms have been developed for use in different types of systems. Such servers often include a plurality of processors which operate to perform specific tasks which the server is given. Such a system is shown in FIG. 1 where the server 10 includes a plurality of processors 12. The processors are connected to a bus to which additional processors or other equipment may be connected. Also connected to the bus is a controller 14 which runs the operating system and thereby controls the operation of the server itself. A memory 16 is also connected to the controller so that system data can be stored for access by the controller.
This server system will also have additional elements connected thereto. A peripheral component interconnect bus (PCI Local bus specification 2.2) 18 allows the controller to be connected to other peripheral components. Other devices may also be connected by way of similar buses to the controller.
Such server systems are now known and operate well in a number of different situations. However, it is always advantageous to find better methods for running such a system. Such improvements can relate to areas such as speed, reliability and power usage. In the area of reducing power usage, a specification has been advanced which helps to manage the power use of such a server through the operating system. The specification which describes these ideas is called the advanced configuration and power interface (ACPI). One of the basic concepts of this specification is to move to the operating system the directed power management. This is different from the systems often used today where power management is only added onto some PC's. This inhibits application vendors from supporting or exporting it. By moving the power management functionality into the operating system, it becomes available on every machine that the operating system is installed on. While the level of power savings will vary, all users will have the power management functionality available.
Furthermore, by having the power management resident in the operating system, it avoids the necessity to work this system through the BIOS (Basic input/output system) structure. The BIOS code has become very complex in regard to power management. Accordingly, the use of the operating system to manage the power usage has great advantages.
In addition to managing the power usage, the ACPI specification provides a more dynamic system configuration. In particular, it is possible to remove or replace parts of the system without shutting down the system as a whole. Thus, various events may be signaled by the hardware to indicate changes such as a configuration change. A system control interrupt is then generated which is executed by the operating system. Once the device is shut down, it may be removed and replaced while the system continues to run. This is referred to as a hot remove event. That is, it is considered hot because the system continues to operate while it is replaced. This arrangement allows the system to be more flexible in its configuration.